In a Long Term Evolution (LTE) system, uplink channels of a terminal include a Physical Uplink Shared Channel (PUSCH), a Physical Uplink Control Channel (PUCCH) and a Physical Random Access Channel (PRACH). Further, data information, a Scheduling Request (SR), Hybrid Automatic Repeat Request Acknowledgement (HARQ-ACK) and Channel State Information (CSI) may be transferred in the PUSCH. An SR, HARQ-ACK and CSI may be transferred in the PUCCH.
In order to meet requirements of an International Telecommunication Union-Advanced (ITU-Advanced), a Long Term Evolution Advanced (LTE-A) system serving as an evolution standard for LTE needs to support a larger system bandwidth (a maximum of up to 100 MHz), and needs to be backwardly compatible with an existing standard for the LTE. On the basis of an existing LTE system, bandwidths of the LTE system may be combined to obtain a larger bandwidth. This technology is called as a Carrier Aggregation (CA) technology, and can improve the spectrum utilization rate of an International Mobile Telecommunications-Advanced (IMT-Advance) system and relieve the shortage of spectral resources, thereby optimizing the utilization of the spectral resources.
In a system to which the carrier aggregation is introduced, a carrier which is aggregated is called as a Component Carrier (CC), also as a Serving Cell (SC). Moreover, concepts of a Primary Component Carrier/Cell (PCC/PCell) and a Secondary Component Carrier/Cell (SCC/SCell) are also proposed. In a system in which the carrier aggregation is carried out, a primary serving cell and a secondary serving cell are at least contained, herein the primary serving cell is in an activated state all the time.
In an existing carrier aggregation system, when there is no PUSCH is sent simultaneously, uplink control information, including an SR, HARQ-ACK and CSI, can only be sent on a PUCCH of the PCell. There is no problem with this manner in the initial stage of the carrier aggregation.
However, the inventor of the present disclosure discovers, in a research process, that with subsequent evolution such as enhancement of small cells, a scenario where all of the small cells are non-co-located will be an important scenario of the CA. In such scenario, if the number of the small cells is huge and the PUCCH is limited to be sent only on the PCell, the overhead of the PUCCH of the PCell will become a problem.
A solution for reducing the overhead of the PUCCH of the PCell is to allow the PUCCH to be sent on the SCell. However, because the PUCCH can be sent only on the PCell in an existing carrier aggregation mechanism, when simultaneous sending of the PUCCH on the PCell and the SCell is supported, some corresponding mechanisms are required to be introduced to be capable of ensuring normal operation of terminals.
An effective solution has not been proposed yet at present for the problem that support for simultaneous sending of the PUCCH on the PCell and the SCell is not provided in the conventional art.